How to Install a Truck Cap

Truck caps not only add aesthetic value to your pickup truck, they also come in handy by helping to safely carry precious cargo or making camping easier. Truck caps are designed for specific makes and models of trucks in order to fit correctly. Be sure to purchase the right cap for your truck. Quality truck caps will come with their own aluminum clamps and will not require drilling into the bed rails to secure them. Newer truck caps have a high mount brake light and some have interior lamps that may require drilling a small enough hole to run wiring to the rear taillight assembly.

Things You'll Need

  • Truck cap and hardware
  • Large blanket
  • Helper/assistant
  • Adhesive foam weatherstripping (single sided)
  • Ratchet and socket set
  • Hand drill and drill bit
  • Wire butt connectors
  • Wire stripper/cutter

How to Install a Truck Cap

  • Spread a large blanket out onto a soft area such as a lawn or unpaved surface.Have an assistant help your flip the truck cap over on its top and onto the surface of the blanket.

  • Apply adhesive foam weatherstripping to the edges around the entire bottom of the truck cap, with the exception of the rear hatch. Make sure the sticky side goes to the cap bottom.

  • Open the tailgate to your pickup truck.

  • Have an assistant help your flip the cap back over and carefully place it onto the bed of the truck. The cap should sit evenly on both sides of the bed.

  • Crawl into the back of the pickup with two of the aluminum hardware clamps. Align the clamps as close to the front of the truck bed as possible and snug them.

  • Close the tailgate to make sure the rear window of the cap can close properly. If necessary, make adjustments to the cap alignment. Once you've achieved the proper alignment, the rear hatch will close and lock correctly.

  • Crawl back into the back of the truck with the two remaining aluminum hardware clamps. Position the clamps so that they are as close to the rear of the truck as possible on the bed rails and tighten all four clamps, using a socket and ratchet.

  • Drill a small hole, if necessary, near the left rear taillight assembly. Make the hole big enough to fit the wiring of the cap.

  • Thread the cap wire into the hole, then remove the rear taillight assembly from the truck to locate the wiring. Locate the brake wire to cut, strip, and butt connect the high mount brake light. Strip a small piece of insulation from the brake wire. Connect the high mount stoplight wire to the trucks brake wire. Install the tail light assembly.